The present invention generally relates to a storage controller, and in particular relates to a storage controller configuring a plurality of I/O processors in a channel controller.
In recent years, the data volume handled by computer systems is increasing exponentially. As a storage controller; that is, a storage system for managing such data, a large-scale storage system managed by a RAID (Redundant Arrays of Inexpensive Disks) system for providing an enormous storage resource known as midrange class or enterprise class is recently attracting attention. In order to efficiently use and manage such vast amounts of data, technology has been developed for realizing high-speed and extensive access to a storage system by connecting a storage system such as a disk array device and an information processing device via a SAN (Storage Area Network). Meanwhile, a NAS (Network Attached Storage) has also been developed for interconnecting a storage system and an information processing device via a network using a TCP/IP protocol or the like, and realizing access from the information processing device at the file level.
In this type of storage system technology, there is a concept known as a NAS head which integrates SAN and NAS. Here, among the constituent elements of NAS, only the controller unit is removed and used as an independent device. By incorporating this NAS head in a SAN-connected storage apparatus, the NAS function can be incorporated into the storage system. For instance, Japanese Patent Laid-Open Publication No. 2005-157713 describes this type of storage system.